Oklahoma won its eighth Big 12 championship Saturday with a 24-17 win over TCU at Amon Carter Stadium. The Sooners are co-champions with Kansas State after finishing 7-1 in the Big 12. Running back Damien Williams showed his big-play ability with two touchdowns, but it was the Sooners defense that won the game for OU. Here's a look at five key plays in the victory.

TCU's pass to tie the game was almost completed but Julian Wilson and Tony Jefferson were in good position.

The Sooners' first touchdown showed just how difficult it can be to stop OU’s offense, because it has so many options.

OU was in its four-receiver set and the Horned Frogs were content to sit back in coverage and take their chances. Williams was initially lined up to the left of quarterback Landry Jones but went in motion, allowing Jones to get a pre-snap read that TCU was in zone defense. When all four TCU defenders on the right side of the field bracketed Sterling Shepard and Justin Brown, Williams went unnoticed along the sideline after Brown’s in route.

It was the decisiveness and accuracy of Jones’ throw that made this play. He caught the TCU cornerback David Jenkins with his head turned and made an outstanding throw to find Williams in stride. The throw had some zip and was extremely accurate, so Jenkins couldn’t do anything about it. As soon as Jones recognized Jenkins and Kevin White inside the numbers, he knew he could find Williams for the touchdown.

This play showed the value of having a pass-catching threat at running back. The Horned Frogs were so concerned with OU’s receivers that they didn’t pay attention to Williams, and they paid for it.

Saunders’ touchdown catch capped off a terrific response by Jones and the Sooners after the senior quarterback’s interception led to TCU’s lone points of the first half. Jones was 6-of-7 on the drive (the lone incompletion was a drop) as he led OU to a touchdown just before halftime.

On third-and-23 with OU in its four-receiver set, the Horned Frogs were, once again, content to take their chances and sit back in coverage. And Jones made them pay again with another good read and accurate throw.

Either TCU believed they could get pressure on Jones without blitzing or cover OU’s receivers well enough that Jones would have nowhere to go. The Horned Frogs were wrong on both counts.

Sooners' third-down stop early in the fourth quarter

With TCU driving to cut into OU’s 24-14 lead, the Horned Frogs faced third-and-4 on OU’s 15-yard line. The Sooners defensive line was up to the task as defensive tackle Jamarkus McFarland got immediate penetration. Defensive tackle Casey Walker won his individual battle to force TCU quarterback Trevone Boykin to completely stop his forward momentum behind the line of scrimmage and try to find a crease. McFarland, Frank Shannon and Chuka Ndulue combined to make the stop. OU’s defensive line dominated on the play and forced Boykin to dance around in the backfield for no gain.

TCU missed a field goal on the next play. It was the first of several key fourth-quarter stops for OU’s defense.

One play after Brown fumbled a punt, Jefferson knocked down a potential touchdown connection between Boykin and Boyce. The Horned Frogs ran play-action fake and Boyce, lined up in the slot, went tearing down the middle of the field on a go route. It was the same play that resulted in Brandon Carter’s 74-yard touchdown earlier in the second half.

Jefferson was lined up between the numbers and the hash marks on the left side of OU’s defense when the ball was snapped. Boyce was in the slot on the right side, just inside the hash marks and ran right by Javon Harris and Julian Wilson, who were looking into the backfield.

Undoubtedly recognizing the same play, Jefferson sprinted toward the middle of the field after the play-action fake, but Boyce was already behind him. Jefferson turned around at the perfect time and knocked away the pass. If he didn’t turn around to see the ball, it’s probably a touchdown. It was an All-America type of play by the junior safety; if he decides to return to OU it will be a major boost to Mike Stoops' defense next season.

The Horned Frogs settled for a field goal on the drive.

Wilson, Jefferson break up TCU’s final pass

It was a well-executed play all around. Boykin made a nice throw, Boyce ran a good route to get free and the Sooners made the play to cement the victory.

Lined up in the slot, Boyce was matched up with Wilson in man coverage. He beat Wilson on a corner route but Wilson, a redshirt sophomore, got his hands between the ball and Boyce’s hands to keep the TCU receiver from securing the catch. Jefferson, using his terrific instincts, arrived just as the ball did and helped break up the pass.

It was a huge play by Wilson in a critical situation. He has been arguably the most pleasant surprise in the secondary, as his versatility has allowed him to match up on receivers of various sizes with success. He should be a big part of OU’s plans for the defense in 2013.

Summary: OU's defense, Jefferson in particular, came up with big plays when the Sooners needed them the most. The Sooners have had their ups and downs this season but they earned their Big 12 co-champion status by finding a way to win in three straight games to end the regular season. OU saw its top players step up in key moments to win games against West Virginia, Oklahoma State and TCU that they easily could have lost. Now, thanks to their stars, the Sooners will get Big 12 championship rings.